Process for producing colloidal metal hydroxides



Patented Apr. 18, 1939 UNITED STATES ass Reference PATENT OFFICE.

PROCESS FOR PRODUCING GOLLOIDAL DIETAL HYDROXIDES Rudolph S. Bley, Elizabethton, Tenn.

No Drawing. Application August 15, 1935, Serial No. 36,438

'7 Claims.

The present invention relates to a process of preparing pure colloidal metal hydroxides especially for therapeutic purposes.

One object of my invention has to do with the controlled decomposition of metal alkyls in the presence of an inert diluent;

Another object of my invention relates to the decomposition of metal alkyls in water while being diluted with an inert gas.

A third object of my invention has to do with a novel synthesis of metal alkyls, especially aluminum triethyl, per se by causing a finely divided metal to react upon diethyl mercury at relatively low temperatures.

A fourth object of this invention relates to the production of metal hydroxide suspensions containing a definite amount of hydroxide particles.

Other objects of my invention will become ap parent to those skilled in the art after a study of the following specification.

Colloidal metal hydroxides have, heretofore, been prepared by interaction of water-soluble electrolytes. In this manner, colloidal aluminum hydroxide, for example, may be formed by causing sodium hydroxide to react upon aluminum sulphate. However, it becomes. almost impossible to thoroughly remove the sodium sulphate adsorbed to the gelatinous aluminum hydroxide, even by prolonged dialysis. These impurities are, however, often detrimental when colloidal hydroxides are used in therapeutics ior injections,

- etc.

Until the present time, it has been practicallyimpossible to form colloidal metal hydroxides from corresponding metal alkyls for the reason that these alkyls ignite and explode in the presence of minute quantities of water. When aluminum triethyl, for example, is introduced into water, colloidal aluminum hydroxide is formed in accordance with the following equation:

In spite of its simplicity, this reaction cannot be carried out due to the aforementioned explosions.

I have found, by experimentation, that colloidal I metal hydroxides can be produced from explosive action is sufliciently retarded to avoid ignition and explosion of the metal alkyl. The inert liquid may be removed from the hydrosol by evaporation, etc. Instead of diluting the metal alkyl with an inert liquid, it may be diluted with an inert gas, such as nitrogen, helium, krypton, neon,

decomposes in water and forms a substantially water-insoluble hydroxide therein.

The metal alkyls, used in the reaction, maybe prepared as follows:

1. By the action of metals on alkyl iodides.

2. By the action of alloys on alkyl iodides.

3. By the action of metallo-organic bodies on metals.

4. By the action of metallic chlorides on metallic-organic derivatives (-zinc alkyls, magnesium alkyl halides, etc.)

Aluminum triethyl, for example, may be.

formed by causing mercury diethyl to react upon finely divided aluminum in an autoclave at about 30 to 145 C. for several hours. The impure aluminum triethyl is then distilled in the com- Dlete absence of water in a column filled with carefully dried carbon dioxide. About 50 to of the theoretically possible yield of aluminum triethyl is obtained in this manner, and it may be preserved for relatively long'periods of time over dry carbon dioxide. The mercury diethyl, employed in the reaction, may be formed by means of the Grignard reaction. Other metal alkyls, such as aluminum trimethyl, beryllium trimethyl, beryllium triethyl, gallium trimethyl, gallium triethyl, zinc dimethyl, zinc diethyl, cadmium. methyl, cadmium ethyl, antimony trimethyl, antimony triethyl, etc., may be produced in accordance with the method set forth above.

When a metal alkyl is slowly introduced into distilled water in the presence of an inert, gaseous or liquid diluent, the corresponding metal hydroxide is formed therein in finely divided form. By regulating the amount of diluted alkyl introduced into a given amount of water, more or less concentrated hydrosols may be obtained.

Search- Boom I These hydrosols, free from electrolytes, will settle their solid phase on standing, and it becomes necessarySto float the particles by means of protective colloids, such as glues, gelatine, etc. It is also possible todetermine first the electric charge ofthe hydroxide particles and then to peptize the same by addition of minute amounts of electrolytes. Aluminum hydroxide particles, for example, have a positive charge, and thus then can be peptized by minute acid additions. Electro-positive particles must be peptized with acids and electro-negative ones with alkalies.

Example 1 About 50 grams of mercury diethyl are heated for several hours in an autoclave with about 10 grams of finely divided aluminum (or another metal) at a temperature of about to C. The impure aluminum triethyl is subsequently purified by distillation over dry carbon dioxide and collected in complete absence of water in a dry flask. Dry nitrogen, for example, is then passed through the flask which is warmed to about 100 C. into distilled water. Although the heating of the alkyl-containing flask facilitates an intimate mixing of the alkyl with nitrogen, excessive heating thereof should be avoided. The aluminum hydroxide formed in the water may be stabilized as set forth above. It must be emphasized that all devices and chemicals used have to be completely dry to avoid explosions.

Example 2 A metal alkyl, such as aluminum triethyl, etc.', is dissolved in an inert liquid, for example, an alcohol, ether, ketone, etc., and the mixture slow- .ly introduced into distilled water to form a colloidal hydroxide. The inert liquids must be completely dehydrated before admixing them with the metal alkyl. The inert liquid, i. e., diluent, need not be a true solvent for the metal alkyl. The alkyl may be also homogenized in the diluent. The distilled water into which the alkyl-diluent mixture is introduced is preferably cooled to retard the reaction. Standardized suspensions may be prepared by adding a fixed amount of alkyl to a predetermined amount of water. The hydroxide hydrosol may, subsequently, be stabilized in accordance with methods set forth in Example 1.

After having described my invention, I wish to emphasize that in the appended claims the term metal alkyl covers only such alkyls which are decomposed by water to form water-insoluble or substantially water-insoluble metal hydroxides. The term inert diluent used in the claims covers only such organic liquids which either dissolve or suspend metal alkyls and which do not interfere with the reaction, 1. e., remain unattacked by the metal alkyl in the water and are removable from the same, and. furthermore, it covers inert gases as set forth in the specification. It is not intended to cover solid substances serving as diluents, because they have been found these modifications as defined by the appended claims.

I claim:

1. The process of producing a colloidal metal hydroxide free from contaminating electrolytes which comprises forming an intimate mixture of an anhydrous, volatilizable diluent and a metal alkyl, causing water to react with said mixture with the formation of a. metal hydroxide in colloidal form and finally removing said diluent from said hydroxide by evaporation, said diluent being incapable of chemically reacting with said metal hydroxide or water.

2. The process of producing a colloidal metal hydroxide free from contaminating electrolytes which comprises forming an intimate mixture of an anhydrous, liquid diluent and a metal alkyl, causing water to react with said mixture with the formation of a. metal hydroxide in colloidal form and finally removing said diluent from said hydroxide by evaporation, said diluent being incapable of chemically reacting with said metal hydroxide or water.

3. The process of producing colloidal aluminum hydroxide free from. contaminating electrolytes which comprises forming an intimate mixture of an anhydrous, volatile diluent and an aluminum alkyl, causing water to react with said mixture with the formation of aluminum hydroxide in colloidal form and finally removing said diluent from said hydroxide by'evaporation, said diluent being incapable of chemically reacting with said metal hydroxide or water;

4. The process of producing a colloidal :metal hydroxide free from contaminating electrolytes which comprises forming an intimate mixture of an anhydrous alcohol and a metalalkyl, cansing waterto react with said mixture with the formation of a. metal hydroxide in colloidal form and finally removing said alcohol from said hydroxide by evaporation.

5. The process of producing a colloidal metal hydroxide free from contaminating electrolytes which comprises forming an intimate mixture of an anhydrous ether and a metal alkyl, causingwater to react with said mixture with the formation of a metal hydroxide in colloidal form and finally removing said ether from said hydroxide by evaporation.

6. The process of producing a colloidal metal hydroxide free from contaminating electrolytes which comprises forming an intimate mixture of an anhydrous ketone and a metal alkyl, causing water to react with said mixture with the formation of a metal hydroxide in colloidal form and finally removing said ketone from said hydroxide by evaporation.

7. The process of producing a colloidal aluminum hydroxide free from contaminating electrolytes which comprises forming an intimate mixture of anhydrous ethylalcohol and aluminum triethyl, causing water to react with said mixture with the formation of aluminum hydroxide in colloidal form and finally removing said ethyl alcohol from said hydroxide by evaporation.

RUDOLPH S. BLEY. 

